1. Field of the Invention
The described technology relates generally to a thin-film deposition mask assembly of a flat panel display. More particularly, the described technology relates generally to a thin-film deposition mask assembly of a flat panel display for attaching a division mask in a mask frame.
2. Description of the Related Art
Conventionally, flat panel displays include organic light emitting displays, liquid crystal displays (LCD), and plasma display panels (PDP). Manufacturing of an organic light emitting diode (OLED) display includes a process for forming an electrode and an organic emission layer with a thin film of a specific pattern. A mask assembly is used for the thin-film deposition process.
For example, the mask assembly includes a mask frame forming an opening, belt-type division masks fixed to the mask frame while tension is applied thereto in the length direction, and sub-masks intercepting neighboring division masks. The division mask includes a plurality of pattern openings to manufacture a plurality of organic light emitting diode (OLED) displays on a substrate array. Each pattern opening corresponds to one organic light emitting diode (OLED) display, and it is formed in the same pattern as the electrode or organic emission layer to be formed on the organic light emitting diode (OLED) display.
As the mask assembly has been enlarged, the length of the division mask has also been increased. Hence, the division mask is increased to remain behind because of gravity, and it becomes difficult to align the division mask and the mask frame, and the mask assembly and the substrate array. To reduce the division mask's to such remaining, tension is applied to the division mask. Therefore, tension is substantially applied to both sides of the frame, and the mask frame is bent inwardly in the tension's vertical direction. That is, a form distortion, such as, a saddle type of distortion occurs in the mask assembly. The form distortion of the mask assembly generates a position error of the pattern from the pattern opening of the division mask, and further increases the error.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.